I took off a project involving a PIC18F252. The code is compiled with CCS and I am just migrating it to MPLAB.
The PIC has 1 UART module, its TX and RX pins are RC6 and RC7. I am not a microchip expert but I have worked a bit on them, and have looked online before posting this question.
The original code is using
#use rs232(baud=9600,xmit=PIN_B5,rcv=PIN_B4,restart_wdt)
As far as I can see, the PIC doesn't permit remapping.
So how is that possible?
What is CCS doing "under the hood"?
So the UART pins are RB4 and RB5?
This:
#use rs232(baud=9600,xmit=PIN_B5,rcv=PIN_B4,restart_wdt)
is an extension of the CCS compiler to write some configuration data into the configuration register of the UART module (e.g. baudrate) and can't be used with the xc8 compiler. Have a look into your datasheet how to setup the UART module.
Related
I am trying to manually set the ISER0 and STIR registrs to invoke interrupt number 3 which is RTC Wakeup Interrup for educational purposes. Here is my code:
I step through the register contents, but somehow the code was not able to write to the ISER0 and STIR registers, as is shown below where i am trying to clear the ISER0 register.
Can someone please explain me what am i doing wrong here?
ISER has one bit for every exception, STIR takes exception number - 16.
In the second image you write 0 to the ISER register. That has no effect as described from both ARM architecture reference manual and STM32 M4 Programming Manual.
I would put a volatile on both register pointers declaration, but in this case I don't think it's an issue.
The issue is solved. Somehow, the stlink debug with openOCD was causing an issue with semihosting enabled to which i have no explanation for now. When I changed the debugging to STLink with SWV viewer, it worked ok...
I bought an RP2040 board with 16MB QSPI Flash Memory in the board:
The Flash Memory w25q128 is connected to QSPI dedicated pins of the RP2040:
I was finding out how to access this data from the RP2040 datasheet:
But I didn't find out how to:
Initialize XIP memory in rp2040 boot;
To flash/access data into the w25q128; and
Run instructions from the External Flash Memory.
I was looking for sample codes at GitHub but I didn't find anything useful for these two items I want.
I also found the 2.6.3.1 section of the RP2040 datasheet but I don't know if XIP cache is what I am looking for...
Does someone have done anything related to that? I am a newbie in this subject, so I would like to sorry if I did something wrong.
Thanks in advance!
In the datasheet there is an hint that this configuration is done by the SDK automatically if certain conditions are met:
Following the github link we get to the assembly source for the second stage bootloader. This answers the question on how to initialize the memory. It's not done by you (unless you are not using the SDK).
Here are the configuration steps:
SSI stands for Synchronous Serial Interface and it's what has to be configured to use the flash as XIP. It's described in the datasheet:
I'm a newly graduated electronics engineer and one of my first tasks in my new job is to import a code to Mbed compiler.
I'm trying to run the Mbed Blinky example on my custom hardware with LPC1769 chip. I've exported the Blinky app to GNU Eclipse from the Online MBED compiler and imported it to the IDE.
The Mbed blinky code runs fine when I set the appropriate led pin(changing LED1 in the PinNames.h from 1.10 to 2.13 for my hardware) and flash it directly. So MBed and my custom HW isn't problematic. However, my firm has a custom bootloader and it's required to use it with any application. The custom bootloader requires that I start the program beginning from 0x4000.
For this my firm was previously adding this line to their code, flashing the bootloader and uploading the IDE's output .bin file to the board with a custom FW loading program.
SCB->VTOR = (0x4000) & 0x1FFFFF80;
When I try to follow the same steps, compiler builds without any complaints, but I see no blinks when I upload the program to my bootloader.
I'm suspecting I have to make some changes to the built-in CMSIS library, and/or the startup_LPC17XX.o and system_LPC17xx.o files come with the MBED export, but I'm confused. Any help would be much appreciated.
Also, I'm using the automatically built make file, in case there's any wonders.
Most importantly, you need to adjust the code location in the linker script, for example:
MEMORY {
FLASH : ORIGIN = 0x4000, LENGTH = 0x7C000
}
Check the startup code and linker script for any further absolute addresses in flash memory.
Adjusting the VTOR is required for interrupts, if the bootloader doesn't already do that. The & operation looks weird; it should be sufficient to simply write 0x4000, or, even better, something like:
SCB->VTOR = (uint32_t) &_IsrVector;
Assuming you have defined _IsrVector in your linker script or startup code to refer to the very first byte in the vector table, i.e. the definition of the initial stack pointer. This way you don't have to adjust the code if the memory layout is changed in the linker script, and you avoid magic numbers.
Upon instantiating a LowPowerTimer, like so:
LowPowerTimer* lowPowerTimer = new LowPowerTimer();
It crashes on my own target. It works 100% on the STM32F429-discovery evaluation board.
What could cause the problem? All other code runs perfectly. There are enough memory and flash. The micro is of the same family. Are there any prerequisites that I do not know of? The micro I'm using is the STM32F413RH with a 26MHz external crystal.
I use the mbed platform and code in C++, FWIW...
My first guess would be that you have not configured the lpticker clock source correctly. Do you have the same crystals as the evaluation board? See which clock source the lpticker is using there and see if it's missing on your final board.
In addition, what is crashing? Do you see a hard fault? Where does it originate from?
So what I found was that in the targets.json file I had to override the lse_available macro. The lse_available macro states that a low-speed external oscillator is connected to the micro - and then the Low Power Ticker would use that as its source. But if you set it to 'not connected', it uses other clock sources.
I am doing an academy project about porting Autosar OS to a microcontroller. After reading papers and information about Autosar, Arctic Core and Arctic Studio, I have some questions:
I used to port FreeRTOS to a microcontroller and it's very easy, I just included some *.h and *.c files of FreeRTOS, and then used the FreeRTOS functions to build my application on the chip. Can I do similarly to Autosar? If it is possible, which files should I include to my main.c
Second question, in FreeRTOS, I only need to use xcreatetask() function(this is a FreeRTOS function) to set task priority, and then i applied vstarttaskschedule() function to run the task in queue however I cannot see these kinds of functions in Autosar OS. Can someone tell me which function in autosar have same functionality like functions I said.
When I program Texas Instrument chips, there is always main function which include the main program that we will build for the chip. However, I don't see any main functions in arctic Core example. How can the chips runs the program without main function?
Please help me answer these questions!
3, You are not able to see to main function in ARTIC core:
AUTOSAR does not define start-up code. You are expected to write main function yourself. Kernel in AUTOSAR OS gets initialized from ECUM module. If you want to boot your OS, you must have ECUM module. Also you should have BSWM module to start schedule tables. You have to create rule in BSWM for RTE start-up and it will start your schedule table.
You have to handcode start-up code (RAM/Register/etc initialization), from that you have to call main function, main function will be handcoded. Call EcuM_init from main function. This way your OS will boot.
2, You are not able to locate function to set task priority and activation:
AUTOSAR does not support dynamic task priority. You have to set all priorities in cofiguration. To run task you can use ActivateTask(). One quick trick to start task at startup is, set parameter OsTaskAutostart for one task. Task for which you have set parameter OsTaskAutostart will get invoked as soon as kernel is initialized.
Your start-up code will be target specific.
ECUM does the initialisation part for all the SW modules within ECU.
Remember to call ECUM from your Main.c
ECUM does initialisation of BSWM, Drivers and the SW modules.
Once RTE is initialised - there is a part SchM within the RTE which schedules the Mainfunctions from each module.
The Mainfunctions from each SW Module are known to RTE by BSWMD and SWCD files.
Read RTE SWS, ECUM SWS, SYSTEMTemplate SWS for more info
I guess your academic project already ended, however porting an AUTOSAR OS to a specific microcontroller is not a suitable scope for an academic project.
Firstly, from your question, I cannot tell if the OS is ARCCORE or other. Secondly, from my experience with FreeRTOS, there is only a limited amount of knowledge which applies to AUTOSAR OS and creating tasks (2.) is application-level rather than porting. Thirdly, the majority of AUTOSAR OS rely on specialised embedded compilers, e.g. GHS or DIAB which are not home to academia.
I have not ported AUTOSAR OS myself, but I suggest taking a look at a ported version, the architecture and file structure, system and then the start-up routines, vector tables, peripheral code, etc. Complexity might be reduced when porting within the same MCU architecture, say Renesas machines or ARM.
To answer your question 3., you will not find the main() within the ARCCORE examples. main() is located in os_init.c and looks like this:
extern void EcuM_Init(void);
int main( void )
{
EcuM_Init();
}
Then, EcuM_Init() [EcuM.c] calls InitOS();